package com.hsyt.pfc.support.util;

import java.security.KeyFactory;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;

/**
 * RSA签名验签类
 */
public class RSASignature{

    /**
     * 签名算法
     */
    public static final String SIGN_ALGORITHMS = "SHA1WithRSA";

    /**
     * RSA签名
     * @param content 待签名数据
     * @param privateKey 商户私钥
     * @param encode 字符集编码
     * @return 签名值
     */
    public static String sign(String content, String privateKey, String encode) {
        try {
            PKCS8EncodedKeySpec priPKCS8    = new PKCS8EncodedKeySpec( Base64.decode(privateKey) );
            KeyFactory keyf                 = KeyFactory.getInstance("RSA");
            PrivateKey priKey               = keyf.generatePrivate(priPKCS8);
            java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMS);
            signature.initSign(priKey);
            signature.update( content.getBytes(encode));
            byte[] signed = signature.sign();
            return Base64.encode(signed);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    public static String sign(String content, String privateKey) {
        try {
            PKCS8EncodedKeySpec priPKCS8    = new PKCS8EncodedKeySpec( Base64.decode(privateKey) );
            KeyFactory keyf = KeyFactory.getInstance("RSA");
            PrivateKey priKey = keyf.generatePrivate(priPKCS8);
            java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMS);
            signature.initSign(priKey);
            signature.update( content.getBytes());
            byte[] signed = signature.sign();
            return Base64.encode(signed);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * RSA验签名检查
     * @param content 待签名数据
     * @param sign 签名值
     * @param publicKey 分配给开发商公钥
     * @param encode 字符集编码
     * @return 布尔值
     */
    public static boolean doCheck(String content, String sign, String publicKey,String encode) {
        try {
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            byte[] encodedKey = Base64.decode(publicKey);
            PublicKey pubKey = keyFactory.generatePublic(new X509EncodedKeySpec(encodedKey));
            java.security.Signature signature = java.security.Signature
                    .getInstance(SIGN_ALGORITHMS);
            signature.initVerify(pubKey);
            signature.update( content.getBytes(encode) );
            return signature.verify( Base64.decode(sign) );
        } catch (Exception e) {
            e.printStackTrace();
        }
        return false;
    }

    public static boolean doCheck(String content, String sign, String publicKey) {
        try {
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            byte[] encodedKey = Base64.decode(publicKey);
            PublicKey pubKey = keyFactory.generatePublic(new X509EncodedKeySpec(encodedKey));
            java.security.Signature signature = java.security.Signature
                    .getInstance(SIGN_ALGORITHMS);
            signature.initVerify(pubKey);
            signature.update( content.getBytes() );
            return signature.verify( Base64.decode(sign));
        } catch (Exception e) {
            e.printStackTrace();
        }
        return false;
    }

    /**
     * 对请求参数进行待加签字符串处理
     * @param params
     * @return
     */
    public static String link2Sign(Map<String, String> params) {
        List<String> keys = new ArrayList<String>(params.keySet());
        Collections.sort(keys);
        StringBuffer stringBuffer = new StringBuffer();
        try {
            for (String key : keys) {
                if (StringUtil.isEmpty(key) || null == params.get(key)) {
                    continue;
                }
                stringBuffer.append('&').append(key.trim()).append('=').append(params.get(key));
            }
        } catch (Exception exception) {
            exception.printStackTrace();
        }
        return stringBuffer.deleteCharAt(0).toString();
    }
}
